Heretofore, modern tennis racquet handles typically have been formed of a pre-molded hard composite material during the racquet compression molding operation. The pre-molded handle then is placed into a mold which defines the finished handle pallet dimensions. The material utilized in forming the handle pallet usually has been a rigid cell-type polyurethane foam which was introduced into the handle pallet mold cavity via a low pressure cast molding type machine. This process produced a handle pallet which was relatively heavy so that only approximately 10-20 grams of lead was necessary to be added to the handle before the injection of the polyurethane foam during the molding operation, in order to conform to conventional head light balance condition specifications. The resulting handle pallet was reasonably hard, having a Shore D hardness of about 40. This rigidity was beneficial in that the edges of the eight-sided or transverse cross-sectional, octagonal-shaped handle pallet were hard and clearly defined even when covered with a leather or synthetic material grip, so that indexing the orientation of the tennis racquet face via manipulation of the handle by the player's hand was facilitated. However, such tennis racquet handles exhibited poor shock absorption and would be too heavy for head heavy balance condition specifications.
In recent years, a modified handle pallet has been developed in which a softer, more elastic material has been molded and slipped on the hard handle pallet structure described immediately above. Such handle pallets generally are very shock absorbent due to their softer nature, wherein the elastic slip-on portion of the handle pallet typically has a Shore A hardness of about 60. This outer handle pallet portion is either low pressure cast molded of polyurethane, or injection molded of KRATON.RTM. rubber then slipped onto the handle in a subsequent manufacturing step. Whether the outer softer handle pallet portion is formed of polyurethane or KRATON.RTM. rubber, either material is much heavier than the hard cell polyurethane foams which were previously the preferred material for forming the entire handle pallet, and therefore even less lead weight is necessary in order to obtain a head light balance condition. However, such racquet handles are deficient in that the indexability of the handle is significantly reduced due to the soft outer portion of the handle pallet. Moreover, such racquet handles also are too heavy for head heavy balance condition specifications. An example of such a racquet handle is shown in FIG. 1 and also is disclosed in U.S. Pat. Nos. 4,984,793 and 4,989,870.
Still another handle pallet design which has been in general use for several years is one in which the octagonal-shaped handle pallet has been simultaneously formed during the racquet compression molding operation. The composite racquet head tube is designed to form the handle pallet shape, therefore eliminating all ancillary operations which, as described above, were necessary to complete the handle pallet. Such a single step method yields a very hard handle pallet resulting in good indexing properties, and further yields a very lightweight handle suitable for head heavy balance condition specifications. However, such a handle typically results in complaints by many players that the handle transmits excessive shock to the player's hand. An example of such a racquet is shown in FIG. 2 and also is disclosed in U.S. Pat. No. 3,702,701.
Tennis racquet designers currently are attempting to solve another problem wherein the center of percussion is too low in the head of the racquet. In order to raise the center of percussion toward the distal end of the head of the tennis racquet, the racquet handles must be made lightweight in order to concentrate the majority of mass in the head area creating a head heavy balance condition. However, in order to aid in producing such a condition, a lightweight handle must be utilized, and as discussed above, the only currently available lightweight handle designs are very hard which, although providing good indexing, transmit undesirable levels of shock to the hand of the player.